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Deficiency in serine protease inhibitor neuroserpin exacerbates ischemic brain injury by increased postischemic inflammation.

Gelderblom M, Neumann M, Ludewig P, Bernreuther C, Krasemann S, Arunachalam P, Gerloff C, Glatzel M, Magnus T - PLoS ONE (2013)

Bottom Line: Not only reperfusion but also tPA itself can induce an inflammatory response.Neuroserpin, an endogenous inhibitor of tPA, is up-regulated following cerebral ischemia.This activation results in a worse outcome further underscoring the potential detrimental proinflammatory effects of tPA.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

ABSTRACT
The only approved pharmacological treatment for ischemic stroke is intravenous administration of plasminogen activator (tPA) to re-canalize the occluded cerebral vessel. Not only reperfusion but also tPA itself can induce an inflammatory response. Microglia are the innate immune cells of the central nervous system and the first immune cells to become activated in stroke. Neuroserpin, an endogenous inhibitor of tPA, is up-regulated following cerebral ischemia. To examine neuroserpin-dependent mechanisms of neuroprotection in stroke, we studied neuroserpin deficient (Ns(-/-))mice in an animal model of temporal focal ischemic stroke. Infarct size and neurological outcome were worse in neuroserpin deficient mice even though the fibrinolytic activity in the ischemic brain was increased. The increased infarct size was paralleled by a selective increase in proinflammatory microglia activation in Ns(-/-) mice. Our results show excessive microglial activation in Ns(-/-) mice mediated by an increased activity of tPA. This activation results in a worse outcome further underscoring the potential detrimental proinflammatory effects of tPA.

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Deficiency in neuroserpin does not lead to alterations of the cellular post stroke infiltrate.(A) Absolute numbers of neutrophils (N), macrophages (Mφ), dendritic cells (DC) and lymphocytes (L) in the CNS-infiltrating cells of wt and Ns−/− mice. Representative plots are shown for CD45high and CD45intermediate cells. Brain macrophages were identified as CD45high, CD11b+, CD11c− and distinguished from microglia by the higher expression of CD45. Dendritic cells were identified as CD45high, CD11b+, CD11c+, neutrophils as CD45high, CD11b+, Ly6G+ and lymphocytes as CD45high, CD11b−, CD11c−. The graphs show the means±SD of 9 animals per group analyzed three days after MCAO in three or four independent experiments. One-way ANOVA with Bonferroni post-hoc test was used to assess statistical significance. (B) Immunohistochemical staining of T cells (CD3), neutrophils (Ly6G) and astrocytes (GFAP) in wt and Ns−/− mice three days after MCAO (scale bar = 50 µm).
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pone-0063118-g002: Deficiency in neuroserpin does not lead to alterations of the cellular post stroke infiltrate.(A) Absolute numbers of neutrophils (N), macrophages (Mφ), dendritic cells (DC) and lymphocytes (L) in the CNS-infiltrating cells of wt and Ns−/− mice. Representative plots are shown for CD45high and CD45intermediate cells. Brain macrophages were identified as CD45high, CD11b+, CD11c− and distinguished from microglia by the higher expression of CD45. Dendritic cells were identified as CD45high, CD11b+, CD11c+, neutrophils as CD45high, CD11b+, Ly6G+ and lymphocytes as CD45high, CD11b−, CD11c−. The graphs show the means±SD of 9 animals per group analyzed three days after MCAO in three or four independent experiments. One-way ANOVA with Bonferroni post-hoc test was used to assess statistical significance. (B) Immunohistochemical staining of T cells (CD3), neutrophils (Ly6G) and astrocytes (GFAP) in wt and Ns−/− mice three days after MCAO (scale bar = 50 µm).

Mentions: tPA has been shown to activate immune cells which could explain the larger infarcts [16]., We used whole brain FACS to analyze the composition of the infiltrating immune cells of the ischemic hemisphere of wt and Ns−/− mice 3 days following reperfusion. In both mice strains, we observed a cellular infiltrate dominated by CD45high/Ly6G+/CD11b+ neutrophils and CD45high/Ly6G−/CD11b+ macrophages followed by CD45high/CD11c+/CD11b+ dendritic cells and by CD45+/CD11b−/Ly6G− lymphocytes (Fig. 2A). There was no statistical difference between wt and the Ns−/− mice. The same was true for immunohistochemical analysis of infiltrating Ly6G positive neutrophils and CD3 positive T cells (Fig. 2B). There was also no difference in the response of astrocytes shown by immunohistochemical staining of the marker protein GFAP (Fig. 2D).


Deficiency in serine protease inhibitor neuroserpin exacerbates ischemic brain injury by increased postischemic inflammation.

Gelderblom M, Neumann M, Ludewig P, Bernreuther C, Krasemann S, Arunachalam P, Gerloff C, Glatzel M, Magnus T - PLoS ONE (2013)

Deficiency in neuroserpin does not lead to alterations of the cellular post stroke infiltrate.(A) Absolute numbers of neutrophils (N), macrophages (Mφ), dendritic cells (DC) and lymphocytes (L) in the CNS-infiltrating cells of wt and Ns−/− mice. Representative plots are shown for CD45high and CD45intermediate cells. Brain macrophages were identified as CD45high, CD11b+, CD11c− and distinguished from microglia by the higher expression of CD45. Dendritic cells were identified as CD45high, CD11b+, CD11c+, neutrophils as CD45high, CD11b+, Ly6G+ and lymphocytes as CD45high, CD11b−, CD11c−. The graphs show the means±SD of 9 animals per group analyzed three days after MCAO in three or four independent experiments. One-way ANOVA with Bonferroni post-hoc test was used to assess statistical significance. (B) Immunohistochemical staining of T cells (CD3), neutrophils (Ly6G) and astrocytes (GFAP) in wt and Ns−/− mice three days after MCAO (scale bar = 50 µm).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3643909&req=5

pone-0063118-g002: Deficiency in neuroserpin does not lead to alterations of the cellular post stroke infiltrate.(A) Absolute numbers of neutrophils (N), macrophages (Mφ), dendritic cells (DC) and lymphocytes (L) in the CNS-infiltrating cells of wt and Ns−/− mice. Representative plots are shown for CD45high and CD45intermediate cells. Brain macrophages were identified as CD45high, CD11b+, CD11c− and distinguished from microglia by the higher expression of CD45. Dendritic cells were identified as CD45high, CD11b+, CD11c+, neutrophils as CD45high, CD11b+, Ly6G+ and lymphocytes as CD45high, CD11b−, CD11c−. The graphs show the means±SD of 9 animals per group analyzed three days after MCAO in three or four independent experiments. One-way ANOVA with Bonferroni post-hoc test was used to assess statistical significance. (B) Immunohistochemical staining of T cells (CD3), neutrophils (Ly6G) and astrocytes (GFAP) in wt and Ns−/− mice three days after MCAO (scale bar = 50 µm).
Mentions: tPA has been shown to activate immune cells which could explain the larger infarcts [16]., We used whole brain FACS to analyze the composition of the infiltrating immune cells of the ischemic hemisphere of wt and Ns−/− mice 3 days following reperfusion. In both mice strains, we observed a cellular infiltrate dominated by CD45high/Ly6G+/CD11b+ neutrophils and CD45high/Ly6G−/CD11b+ macrophages followed by CD45high/CD11c+/CD11b+ dendritic cells and by CD45+/CD11b−/Ly6G− lymphocytes (Fig. 2A). There was no statistical difference between wt and the Ns−/− mice. The same was true for immunohistochemical analysis of infiltrating Ly6G positive neutrophils and CD3 positive T cells (Fig. 2B). There was also no difference in the response of astrocytes shown by immunohistochemical staining of the marker protein GFAP (Fig. 2D).

Bottom Line: Not only reperfusion but also tPA itself can induce an inflammatory response.Neuroserpin, an endogenous inhibitor of tPA, is up-regulated following cerebral ischemia.This activation results in a worse outcome further underscoring the potential detrimental proinflammatory effects of tPA.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

ABSTRACT
The only approved pharmacological treatment for ischemic stroke is intravenous administration of plasminogen activator (tPA) to re-canalize the occluded cerebral vessel. Not only reperfusion but also tPA itself can induce an inflammatory response. Microglia are the innate immune cells of the central nervous system and the first immune cells to become activated in stroke. Neuroserpin, an endogenous inhibitor of tPA, is up-regulated following cerebral ischemia. To examine neuroserpin-dependent mechanisms of neuroprotection in stroke, we studied neuroserpin deficient (Ns(-/-))mice in an animal model of temporal focal ischemic stroke. Infarct size and neurological outcome were worse in neuroserpin deficient mice even though the fibrinolytic activity in the ischemic brain was increased. The increased infarct size was paralleled by a selective increase in proinflammatory microglia activation in Ns(-/-) mice. Our results show excessive microglial activation in Ns(-/-) mice mediated by an increased activity of tPA. This activation results in a worse outcome further underscoring the potential detrimental proinflammatory effects of tPA.

Show MeSH
Related in: MedlinePlus